Prevalence and diversity of and other amoeba-resisting bacteria in domestic drinking water systems.

A growing number of human infections incriminate environmental bacteria that have evolved virulent mechanisms to resist amoebae and use them as a replicative niche. These bacteria are designated amoeba-resisting bacteria (ARB). Despite the isolation of these ARB in various human clinical samples, the possible source of infection remains undetermined in most cases. However, it is known that the ARB for instance, causes a respiratory infection in susceptible hosts after inhalation of contaminated water aerosols from various sources. The order contains many ARB, such as or previously implicated in human respiratory infections with no identified contamination sources. We thus investigated whether domestic water systems are a potential source of transmission of these to humans by using amoebal culture and molecular methods. Other important ARB such as mycobacteria and were also investigated, as were their possible amoebal hosts. This work reports for the first time a very high prevalence and diversity of in drinking water, being detected in 35 (72.9%) of 48 investigated domestic water systems, with members of the family being dominantly detected. Furthermore, various and mycobacteria species were also recovered, some species of which are known to be causal agents of human infections.